Which are the go-to components for a dedicated mining rig?

[Janus67]

To clarify the thread title, what main components (outside of video cards) are the general go-to parts to get for a 4-6GPU dedicated mining rig? Of course it would be nice to get the ASRock H81 BTC board, but those are so hard to find for retail that many people look for cheap alternatives. The real question is... what are the best alternatives that won't break the bank?

CPU
I know many use the cheaper sempron/celeron CPUs, does the lack of available cores hurt the mining power in a way?

Motherboard
What motherboards are able to handle 4-6 GPU connections with (presumably) powered risers without burning down a PCI-E slot?

Memory
How much RAM do you generally put into the systems? I've found that on at least vertcoin 16GB of RAM may be necessary in order to mine with 4 GPUs with high TC and Intensity.

Case (or lackthereof)
There are many professional-looking racks that were hand-made, but for those without the skill (or without the tools) is the "best" setup using milk crate-style setups with some PVC pipe to hold the floating GPUs?

Power Supply(ies)
We've had a discussion on the value of getting a high-efficiency PSU (gold/platinum) over Bronze and it looks like while ideally it will be saving you money at the wall, it will take months (and possibly a couple years) to earn back the cost of power that was saved. Which type (single vs multi rail) and how much wattage do you shoot for? What do you do when a single system is having trouble with even two power supplies? Have you just done the paperclip mod to force a PSU?

Risers
Which risers are generally the standard? Do you go with the powered variety to be safe? Are you using the ribbon cable style or have you moved over to the USB plug versions?

Cooling
What do you plan to do about cooling everything? With Spring then summer in the near-future using the outside environment with windows open will no longer be an option. How do you plan to cool your system(s)? Are you setting up a dedicated air conditioner or just hoping for the best in your basement?

Power Delivery
Are you making modifications to your house to assist in the proper amount of power delivery to the wall jacks you are using to prevent blowing a fuse/circuit? If so what have you had done and how much power from the wall was necessary for you to have it done?


Thanks for your help. Using PCPartPicker probably wouldn't be a bad idea if you have a general build that you follow. I can include those in the top of the post/thread if we have a decent number of agreed-upon submissions.

 

[cultist]

Bump!!

 

[ZL1]

although i currently run two dedicated 2 card systems bc the boards only support 2 gpus, not very efficient and I plan to go with a 4 gpu rack soon enough, the cheapest and guaranteed to work 4 card setup is:
asrock extreme4 970 am3 + sempy 145, worst come to worst you can unlock the 2nd core, although nearly no miners ever need much cpu
psus: well gold and plat of course help over time and since mining is a long term kind of thing, it of course helps to have one

other good alternatives for 4+ gpus are:
gigabyte GA-B75-D3V + celeron dual or pentium dual (i prefer the pentiums)
msi z77a-gd45 + cel/pent

 

[KonaKona]

YACoin also uses very high system mem, more or less equal to however much you have on your GPU. 4 4gb cards = a bit under 16gb system ram needed. Ouch.

 

[eaglescouter]

Motherboard:
Z87 limit is 4 GPU's.

CPU:
Cheap. Horsepower is not required here for dedicated mining rigs.

RAM:
4GB is enough to easily run a 4 GPU dedicated BAMT mining rig.

Electrical:
Dedicated 20 amp circuit run to my mining room in addition to the normal shared 15 amp circuit.

Case:
Open aluminum frame.

Cooling:
Thermostatically controlled box fan exhausting out open window.

Risers:
Powered ribbon risers on all cards.

 

[Janus67]

another popular board seems to be the:
https://bitcointalk.org/index.php?topic=461637.msg5111084#msg5111084

GA-990FXA-UD3

may try to pick one up and a sempron cpu.

 

[Fever]

Z87 is not limited to 4 GPUs, I have 5 MSI Z87-G45 boards running 6 280x each.

My favorite board by far is MSI's Z77 Mpower. Have 2 of those running 7 7970/280x each and they have an AUX 6 pin connector to supply power to the PCI-e slots.

Get the cheapest CPU you can find, has no impact on GPU mining at all. I underclock all my Celerons as low as they go.

For risers, whatever floats your boat / is cheapest. USB apparently negates the need for presence shorts on PCI-e slots, and are easier to work with.

Case? None. Build yourself a custom wood or aluminum rack to get a minimum of 2" between each card. (More the merrier)

RAM? 4GB is plenty in most cases with scrypt. Running 280x/7970 requires 2 threads instead of 1, and 4GB will only get you to a TC of about 8192 or so, which in 99% of cases is perfect. More RAM will allow higher TC.

PSUs? Seasonic/Flextronics/Delta/Superflower all the way, in no particular order. I'm currently replacing all 1250w Seasonics with IBM branded Delta made 2000w server PSUs. 30$ for 2000w of unbeatable power supply quality and electrical stability. I think these were originally worth around 2000$. 91% efficiency at 100% load, and they will work at 100% load for 400000 hours. RC groups have pulled 2800w 12v from there without issue. 164A of 12v goodness. Downside is they only output 12v, so you need a cheapo PSU to power the motherboard.

For cooling, yeah... You don't want a lot of cards in your house during the summer time. You'll need a garage if you don't enjoy cooking yourself. 14 cards have kept my entire house warm all winter (Canadian winter) with some clever fan positioning.

For power, you'll want to run your equipment on 240v, not 120v. Efficiency will go up 2 or 3 percent on your PSUs, and they will pull only half the amperage that they would on 120V allowing you to double your capacity per circuit.

Copper wiring:
14AWG = 15A
12AWG = 20A
10AWG = 30A (sweet spot for price/w and cheap PDUs)
8AWG = 40A

Remember to de-rate circuits by 20%. Aluminum wiring needs to be bigger than copper. Also remember that you can convert existing outlets to 240v simply by changing breakers to 2 pole, just make sure you know what outlets are on that circuit and change to appropriate wall sockets if only to prevent 120v equipment from frying. Baseboard heaters can also be easily converted to 240v outlets. Generally they have 20AWG wiring, so 20A.

Typed this out on my phone, sorry if things are too brief/unclear.

 

[gsrcrxsi]

RAM? 4GB is plenty in most cases with scrypt. Running 280x/7970 requires 2 threads instead of 1, and 4GB will only get you to a TC of about 8192 or so, which in 99% of cases is perfect. More RAM will allow higher TC.

this isnt necessarily true.

7970/280x dont REQUIRE 2 threads, but in most cases they certainly hash better in that configuration
TC isnt limited that much by system ram. I have a 7950 running 20,000+ TC just fine with 4GB of ram. the problem comes with the 7970/280x BECAUSE youre running 2 threads instead of 1. TC is more dependent on Intensity level than anything else.

 

[Fever]

this isnt necessarily true.

7970/280x dont REQUIRE 2 threads, but in most cases they certainly hash better in that configuration
TC isnt limited that much by system ram. I have a 7950 running 20,000+ TC just fine with 4GB of ram. the problem comes with the 7970/280x BECAUSE youre running 2 threads instead of 1. TC is more dependent on Intensity level than anything else.

It's very true. a 7970/280x is best run on 2 threads, and 4GB will be maxed out at TC 8192. A card that uses 1 thread will be limited somewhere around TC 21000~23000 with 4GB of RAM. Intensity has nothing to do with TC or RAM.

 

[gsrcrxsi]

intensity has A LOT to do with TC, they are inherently linked.

higher intensity requires higher TC. lower intensities allow lower TC to be used. ive tested and proved this many times.

i've run TC 24000+ on my 7950 without issues.
many people run TC 30000+ on 290s without issues (and 4GB system ram)

say you have a 7950 running -g 1, -TC 15232, -I 13. if you bump the intensity up to 20, you will no longer be able to run TC that low as you'll start getting HW errors. but upping the TC to 20,000+ fixes the issue.

saying TC and I arent linked is just wrong.

 

[KonaKona]

I think the point that fever was getting at is that your intensity alone does not change your GPU or system ram use. Yes, you need more TC (and ram, sometimes just gpu ram and sometimes GPU and system) to run higher intensities, but I'd also argue that it depends on what coin you are mining (and what kind of card).

For me, normal scrypt doesn't really give a hoot what my TC is, it just doesn't like anything over I 13. YACoin will soak up as much graphics ram as I can toss as it and uses that much system ram as well, and how much ram gets thrown at it makes a difference exactly what (raw) intensity it can run at and subsequently the hash rate it gets.

If I had to guess I'd say most of the new coins that come out that are worth mining are going to lean towards more "high N" style work, so I think it'd be safe to say if you want a flexible mining rig, match your gpu ram with system ram. That also makes large scale mining much more expensive when you are paying for 4-6gb of system ram to go along with each GPU.

I wonder if there are any rigs that take ECC DDR2 that you can toss a bundle of GPUs at? The stuff is cheap as heck on ebay...